Lee is accused of murdering Erin Corwin, 19, his then-neighbor in Twentynine Palms, and disposing of her body in a 14-story abandoned mine shaft in the desert near Joshua Tree National Park, officials said.

The cause of Corwin's death has not been released, but an arrest warrant released last week said .22-caliber "fired cartridge casings and pieces of rebar" were found at the scene. They are similar to casings found in Lee's vehicle and residence, according to the warrant.

Lee was arrested in Anchorage, Alaska, a day after Corwin's body was found, ending a nearly eight-week search for the woman in 300 acres of desert.

Corwin and Lee, who is married, may have been having an affair that began February, and she may have been three months pregnant with his child when she disappeared on June 28, both Corwin's friend and Lee's neighbor told investigators, according to a search warrant.

Corwin told her husband, Marine Cpl. Jonathan Corwin, she was going to Joshua Tree National Park to look for hiking trails. He reported her missing the next day.